HP laserjet 1300 causes pc to random reboot?

[grasshopperbe]

i am experiencing a pretty strange problem on 2 printers at work. about a year ago, we bought a new pc for one the secretaries, with 2 of these printers. one for the new pc, and the other one on an old pc in the laboratory (printing out results etc..)

On the old pc (cele 500mhz) the printer was hooked up on the lpt cable, and it always worked without any problems.
On the new pc (athlon64) it's hooked up via USB. Now this pc has been random rebooting since day 1. sometimes several times per day, sometimes once every few days. Because i didn't think of the printer as the cause of the problem, literally every part in that pc has been replaced, without any luck.

now recently we started outsourcing the laboratory work, so the other printer was no longer used.
I was asked by the other secretary if i could replace her old printer with that one because it prints a lot faster . I hooked it up to her pc yesterday(on usb port), and since this morning her pc has "random rebooted " 3 times!
This pc never had any problems whatsoever.

Can this be caused by the printers? this seems very weird to me, but i guess it's the only logical conclusion.
Would it help if i switched both printers from usb to lpt?

[glc]

If a printer offers both LPT and USB, you are always better off using LPT if the computer has a LPT port available.